In general, a rotation operating device provided to a vehicle cabin interior of an automobile, for example, includes a rotation operating member receiving a rotation operation while being held in fingers or the like and a detection device outputting a detection signal corresponding to a direction and amount of the rotation operation. A rotary encoder can be employed as the detection device, however, such a rotary encoder is typically expensive, and therefore performing detection of the rotation operation with an inexpensive switch in place thereof has been considered.
As a rotation operating device employing such a switch, the device shown in FIG. 9 is conventionally known (FIG. 6 of Patent Literature 1). This device includes a dial (not shown in the drawing) receiving a rotation operation, an operating body 2, and a rotation detection switch 3.
The operating body 2 is connected to the dial so as to integrally and coaxially rotate with the dial. The outer circumferential surface of the operating body 2 has a shape in which the rotation detection switch 3 is intermittently operated in conjunction with rotation of the operating body 2. Specifically, the outer circumferential surface includes a plurality of projections 5 projecting outwardly in a radial direction and, in addition, the projections 5 are intermittently aligned in a circumferential direction.
The rotation detection switch 3 is mounted on a circuit board not shown in the drawing and includes a sensor 4 and a plurality of terminals 6A, 6B, and 6C. The terminals 6A-6C are connected to the circuit board. The sensor 4 is attached to a main body of the rotation detection switch 3 so as to be swingable around an axis 8 parallel to an axis at a center of rotation of the operating body 2; is intermittently in contact with the projections 5 in association with the rotation of the operating body 2; and, in addition, is positioned so as to rotate codirectionally with a displacement direction (rotation direction) of the projections 5 accompanying the contact therewith.
The rotation detection switch 3 outputs a signal corresponding to the rotational direction of the sensor 4. Specifically, the dial and the operating body 2 are rotatingly operated in a clockwise direction, as shown in FIG. 9(b). In association therewith, the sensor 4 intermittently dips in a direction (a left direction in the drawing) corresponding to the rotation direction, and each time an electrical signal is output from the terminals 6A and 6B to the circuit board. In an opposite manner, the dial and the operation body 2 are rotatingly operated in a counter-clockwise direction, as shown in FIG. 9(c). In association therewith, the sensor 4 intermittently dips in a direction (a right direction in the drawing) corresponding to the rotation direction, and each time an electrical signal is output from the terminals 6A and 6C to the circuit board.
Accordingly, a determination is made of the terminals outputting an electrical signal from the rotation detection switch 3 and, from the number of outputs therefrom, a rotational direction and rotation amount of the dial are obtained.
With the rotation operating device described above, the rotation detection switch 3 must be provided in the vicinity of the operating body 2, increasing the necessary surface area of the circuit board by an amount of space required for such placement. Moreover, in order to give a user feedback for a rotation operation in conjunction with rotation detection of the dial, a mechanism (for example, a clicking mechanism) which imparts operational feedback must be provided separately from the rotation detection switch, requiring further space for such placement.